The subject matter of the present invention relates to perforating guns for use in connection with oil wellbores, and more particularly, to an insert and twist method and apparatus adapted for securing a shaped charge case, including the charge liner, to a loading tube of the perforating gun.
In a perforating gun adapted to be disposed in a wellbore, a shaped charge is inserted into a mating hole of a loading tube, and a charge retention apparatus holds the charge firmly within the mating hole. The charge retention apparatus normally include retaining rings, charge retention jackets, clips, or bending tabs, all of which are designed to secure the shaped charge to the loading tube. When the shaped charge detonates, the charge retention apparatus will shatter into a multitude of pieces producing debris which will fall to a bottom of the wellbore. However, this debris can ultimately interfere with other operations taking place within the wellbore. Consequently, it is desirable to provide a method and apparatus for securing the shaped charge to the loading tube of a perforating gun without using a separate charge retention apparatus, such as retaining rings or clips or bending tabs, to secure the shaped charge to the loading tube.